Berlin 2015 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 42: Mechanical Properties I
MM 42.3: Talk
Wednesday, March 18, 2015, 16:15–16:30, TC 010
Atomistic Simulations of Dislocation-Interface Interactions in the γ/γ’ Microstructure in Ni-base Superalloys — •Aruna Prakash, Julien Guénolé, Juan Wang, and Erik Bitzek — Materials Science and Engineering, Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
Single crystal Ni-base superalloys are characterized by an ordered L12 γ’-phase (comprising mostly of Ni3Al) that precipitates as cuboidal particles in the face centered cubic (fcc) γ-channels comprising mainly of Ni. The interaction of dislocations in the channels with γ’ precipitates plays an important role for the high-temperature mechanical properties of Ni-base superalloys. To date, most atomistic simulations concerning dislocation interface interactions in such materials have been performed with simplistic quasi-2D geometries. Here we report on simulations performed with a full 3D setup obtained by a novel approach that facilitates the reconstruction of experimental microstructures obtained from atom probe tomography. The reconstructed sample allows us to study the interaction of the relevant dislocations (screw and 60 degree) with a realistic curved interphase boundary, both in samples with ideal stoichiometric chemical composition and with concentration gradients of specific atoms. Static calculations as well as molecular dynamic calculations were performed to determine the interaction of the channel dislocations with the misfit dislocation network. The results of the simulations with the above setup are compared with those from a canonical quasi 2D approach and a 3D model and are discussed in the framework of a multiscale approach.